and i do think the costume is cool, but its just his normal costume in all black. the actual black costume was different, check out the link i posted above for some pics of it.
also, with the symbiot the costume wasnt actually a costume. The symbiot, which happened to be black, formed the costume. as far as i know (i could be wrong as ive not read all the comics, so am basing this mainly on the cartoon) he didnt need his web shooters any more (which the movie doesnt have anyway) but rather the costume would create the web.
In the cartoon, the symbiot also formed his regular clothes (or other 'disguises'), so when he got rid of it he was left in only boxers.
the symbiot being the spidey costume is also why his black costume is very similar to how venom appears. Think of the venom costume without the crazy face and fangs (just a normal head) and in the same build as spidey and you have spideys black cosutme. I do remember hearing/reading that spidey had made an actual black costum in design of the one he had with the symbiot but dont really know the details on that (if he used it, for how long, my guess would be if he used it once venom showed up he went back to the red/blue)
-Darth Simon